1. Field of the Invention
The present invention relates to the field of video communication and more particularly to a method and system of preparing images for wide screen displays in video communication.
2. Description of the Related Art
Recently, a new type of video display, known as a Wide Screen display, has been introduced into the market. As is known, the aspect ratio of a video display or screen is the ratio of the width of the picture to the height of the picture. Common video screens have an aspect ratio of about 4:3. In contrast, a wide screen display has an aspect ratio of about 16:9, which is about the same aspect ratio of cinema screens. For most current TV sets, the aspect ratio is about 4:3. For a high definition TV (HDTV), the ratio is about 16:9. An exemplary resolution of a wide screen display may be about 1024×576 pixels (width×height), while the resolution of a common video display is about 640×480 pixels. Common resolution for video communication is Common Intermediate Format (CIF), which is about 352×288 pixels. To match the aspect ratio of a video display of about 4:3, the aspect ratio of a pixel for CIF is about 12:11. The 12:11 aspect ratio for each pixel creates an image with an entire aspect ratio of (352*12) to (288*11), which is about (4224:3168) or (4:3).
Common video communication equipment, which includes but is not limited to a Video Communication Control Unit (VCCU) or endpoints, normally uses video images with resolutions such as Quarter of Common Intermediate Format (QCIF), CIF, or 4CIF (four times Common Intermediate Format) with an aspect ratio of 4:3. An exemplary VCCU may be a Multipoint Control Unit (MCU), a Multimedia Gateway, etc. Typically, a VCCU serves as a switchboard and/or conference builder for the network. In operation, the VCCU receives and transmits coded video streams to and from various user terminals or codecs. A Multipoint Control Unit (MCU) is conference controlling equipment typically located in a node of a network or in a terminal. The MCU receives several channels from access ports, processes audio and visual signals according to certain criteria, and distributes the processed signals to a set of connected channels. An example of an MCU includes the MGC-100, which is available from Polycom Inc., the assignee of the present disclosure. The MCU is a video communication controller that can be used in other types of video communication. It should be noted that the terms “MCU” and “VCCU” may be used interchangeably in the present disclosure.
An endpoint or a terminal is an entity on the network and is capable of providing real-time, two-way audio, visual, and/or data communication with other terminals or with the MCU. Currently, if an endpoint is associated with a wide screen display instead of a common 4:3 screen display, the endpoint as well as the other endpoints and the VCCU that are involved in the same video conference are not aware of the aspect ratio of 16:9 for the wide screen display. Therefore, the video image that the wide screen display receives from its associated endpoint has a common aspect ratio of 4:3. Typically, a wide screen display has three main types of settings, and a user may set the wide screen display using the control panel on the wide screen display to one of these settings. Currently, an image with an aspect ratio of 4:3 may be displayed on a wide screen display using one of the settings described below in conjunction with FIGS. 1A–1C.
Referring to FIG. 1A, a wide screen display 110 set to a normal setting shows a video image 112. In the normal setting, the video image 112 is displayed as is on the wide screen display 110. In other words, the video image 112 has the aspect ratio of 4:3, while the wide screen display has the aspect ratio of 16:9. Therefore, portions of the wide screen display 110 are not used, as illustrated by the black sections 114 in FIG. 1A.
Referring to FIG. 1B, a wide screen display 110 set to a zoom setting has a video image 120. In the zoom setting, the video image 120 is symmetrically enlarged by the internal electronics of the wide screen display 110. Therefore, portion of the image, in the top and/or the bottom, is cropped. Unfortunately, the cropped area can be an important part of the image, such as the face of a participant.
Referring to FIG. 1C, a wide screen display 110 set to a wide setting has a video image 130. In the wide setting, the electronics of the wide screen display 110 enlarges the regular image by asymmetrical factors so that the enlarged image substantially fits the wide screen display 110. To convert the regular aspect ratio of 4:3 to the wide screen aspect ratio of 16:9, the width of the regular image is increased by a factor of four, and the height is increased by a factor of three. The result is a distorted image 130, as shown in FIG. 1B. For example, a circle becomes elliptical, and a person becomes stretched wider. It is understood that wide screen displays may use other terminology for the ‘normal’, ‘zoom’ and ‘wide’ settings. In addition, other wide screen displays may have additional settings, which can be a combination of one or more of the above settings.
Current techniques for connecting a wide screen display to a video communication, as described above in conjunction with FIGS. 1A–1C, are insufficient. Therefore, a need exists in the art for a system and method for connecting a wide screen display to a videoconference. The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.